My EB2 based I-485 application is pending,
and I have an EAD already. Can I start a company and work for myself using the
EAD? Is there any problem for my I-140 approval later?

Answer:

With an EAD, you can join any company or business, including having your own
company. But you should not work for yourself full-time, because you may have
potential problems with USCIS about the question of your ability to pay the
salary, and meeting other requirements of AC-21 portability.

If you work for your won business in part-time
and you also have a full-time job, then it should not be a
problem.